Filling levels of containers and silos may be determined automatically with the use of filling level sensors, and the measured values can be transmitted (conveyed), by way of field bus connections, to higher-order control systems or servers. Subsequently, within local networks or by way of corresponding internet connections, these measured values can be conveyed to a client computer where they can be displayed.
Either no mechanism for access control may be provided, or access control may take place on the server side by way of preparation of an individual user account for each data set that is to be retrievable by the client computers. In this arrangement, in the client computer in each instance of access a login to the user account may need to take place. However, usually the user accounts relate to altogether different aspects, namely the rights to manage entire projects; setting up measured value views; setting up notification actions; allocating devices to projects; etc.
There is thus a risk in that the operators of a client computer receive far more rights or authorizations than is necessary and sensible for the application case of pure data consumption. At the same time, on the server side the list of the defined user accounts may become unnecessarily long and complex.
The above may result in the mixing of thematically completely different tasks within the list of the user accounts. There may be a considerable danger of, for example, user accounts that originally were intended only for users with exclusive data consumption, at a later point in time as a result of a change in the settings of the user account, receiving unintended permission for modifying projects. There is also a further problem in that details of access authorization may be hidden in the user accounts and that even for the system administrator it is time-consuming and complex to ensure and understand which addressees already use automatic access to measured value information by way of client computers. There is also a further problem in that, in contrast to the situation relating to owners of user accounts, which owners usually have quite extensive insight into the project data, the consuming client computers frequently are to receive only the data of individual measuring points.
Thus, frequently a granular structure of access control at the level of measuring points may be required, which in turn may result in an considerable increase of the list of user accounts. In this context the term “granular” refers to a situation in which in the presence of a complex project structure (project with a large number of individual measuring points which in turn are multiply grouped and subdivided within the project) instances of access authorization to very “small units” (in other words for example only 1 or 2 measuring points) are made possible.
It should be pointed out again that a 1:1 linkage of a certificate with precisely one measuring point is not mandatory. While the aforesaid may exist, it is likewise provided for a certificate to be associated with a data object comprising several measuring points.
Furthermore, in the context of internet applications the use of proprietary transmission protocols has been shown to be problematic and expensive.